The 37-year-old former Juventus and Italy forward is understood to have turned down offers from Liverpool and Southampton, as well as clubs in the Middle East, China, Argentina, the United States and Switzerland to move to Australia's A-League.

"For the next two years I suppose I can say that I'll be Australian," Del Piero said on Wednesday. "I'm starting a splendid and fantastic adventure. I couldn't have chosen a better situation or a better place.

"We touched all the continents. This choice is far away in terms of kilometres but it's very close in terms of philosophy. … I can't wait to go and discover a country that everyone describes to me as fantastic."

Del Piero will become the highest-paid athlete in Australia's four football codes, including rugby league, rugby union and Australian Rules. But he insisted he is moving to Sydney to win things.

"I'm not going there for a vacation," he said. "I'm going there with total dedication."

The A-League, which has had several teams fold in the last two years due to financial problems and dwindling attendance, needs Del Piero as a draw card.

He was a member of Italy's 2006 World Cup-winning team and scored a club record 286 goals in all competitions over 19 seasons with Juventus, although he managed just five last season and only two in Serie A as the Turin club won its first Italian league title since before the 2006 match-fixing scandal.

"We're honoured to have Alessandro sign for Sydney FC," said the Australian club's chief executive Tony Pignata. "It's a momentous occasion."

Sydney's chairman Scott Barlow added: "This is for all Australian football fans. Alessandro Del Piero is a global icon of the game."

The A-League's other marquee signings have included Dwight Yorke, who also played for Sydney in 2005-06, and Robbie Fowler, who played with the now-defunct North Queensland team and Perth Glory from 2009-11.